The onboard systems now available on the market, such as in particular the digital assistants, microprocessor or micro-controller cards, cards of the PCMCIA type, portable data processing units, also called “notebook” or “sub-notebook”, have as common characteristics, often contradictory, the reduction of their size and footprint and the increase in their functionality, using, in particular, the continuous progress in the computation power of microprocessors or micro-controllers onboard in them.
Due to the above-mentioned evolution, the onboard systems tend to reproduce in the most possible faithful manner any microcomputer functionality, except however the functionalities offered by a possible connection of equipment or items peripheral to them.
Among one of the types of the functional mode of onboard systems likely to limit the reconciliation of their functionalities with those of micro-computers, the one relating to the management mode of the available memory space seems critical, because, for the time being, such a management mode seems reduced to the minimum.
Indeed, if the onboard system is made of a card with a microprocessor, also called chip card, as shown on FIG. 1, this onboard system marked 10 comprises classically some input/output circuits I/O, marked 12, information processing resources, marked 14, made of a micro-controller and connected to the input/output circuits 12. Further, a non-volatile memory 18 is provided, which consists of a programmable memory 18a and a ROM memory, or a memory with reading access only 18b. Finally, a working memory RAM marked 16 is also provided. These memories are connected to the micro-controller or microprocessor 14 via a BUS link. The whole is managed by an operating system OS, which can be onboard in the non-volatile memory 18. Finally, in some cases, the microprocessor card may have a CRYPTO calculation unit SI, marked 20, itself connected to the microprocessor 14, and acting, somehow, as a dedicated co-processor.
The microprocessor itself may be replaced or completed by logical circuits onboard in a semiconductor chip, such logical circuits being possibly ASCI-type circuits (Application Specific Integrated Circuits).
Management of the memory field is classically executed, for installing for instance multiple applications, by a reference made of a pointer, linking a starting address with an end of memory field address relating to an application.
When executing these applications, packs of data relating to such applications are written at any address in this memory field, the only criterion for memory allocation and for writing being a criterion of free memory field sufficient between a beginning pointer and an end pointer, to allow memorising a pack of data of a known size.
With successive applications installation/de-installation procedures in the corresponding memory field, free memory field spaces are created in which object code packs, or data, may be written and memorised.
Such an operation process leads to a breaking-up phenomenon, also called fragmentation, for the memory field considered.
The above mentioned breaking up or fragmentation has, just as in case of fragmentation of the hard disk memory field in microcomputers, grave inconveniences, such as the slowing down of considered applications or programmes execution, and the non optimised use of the memory field for the onboard system.
This invention has the aim of remedy the above mentioned inconveniences in onboard systems of the previous art.